(1) Field of the Invention
This invention relates to rechargeable electrochemical cells. More particularly, this invention relates to such cells in which the anode comprises an alloy of sodium and one or more other metallic and non-metallic elements.
(2) Prior Art
Lithium and lithium alloys have been suggested for use as the negative electrode of electrochemical cells. For example, U.S. Pat. No. 4,002,492 discloses elecrochemical cells having an anode consisting essentially of lithium aluminum alloys that contain lithium in amounts between about 63% and 92% and the balance essentially aluminum. Anodes composed of lithium and aluminum are also disclosed in Rao, et al., J. Electrochem. Soc. 124, 1490 (1977), and Bensenhard, J. Electroanal. Chem., 94, 77 (1978). European Pat. No. 0070107; Murphy et al., J. Electrochem. Soc., 126, 349 (1979) and Murphy et al., Mat. Res. Bull., 13, 1395 (1978) disclose batteries based on lithium and sodium intercalation in layered dichalcogenides.
In J. O. Besenhard and G. Eichinger, J. Electroanal. Chem., 78, I (1976), at pages 8 and 9 describe the difficulty of redepositing sodium metal at room temperature from non-aqueous solutions.